Large graphene-induced shift of surface-plasmon resonances of gold films: Effective-medium theory for atomically thin materials
Large graphene-induced shift of surface-plasmon resonances of gold films: Effective-medium theory for atomically thin materials
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DOI：
10.1103/physrevresearch.2.013008
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发表时间：
2019-04
影响因子：
4.2
通讯作者：
Md Kamrul Alam;Chao Niu;Yanan Wang;Wen Wang;Yang Li;C. Dai;T. Tong;X. Shan;E. Charlson;S. Pei;X. Kong;Yandi Hu;A. Belyanin;G. Stein;Zhaoping Liu;Jonathan Hu;Zhiming Wang;J. Bao
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文献类型：
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作者：
Md Kamrul Alam;Chao Niu;Yanan Wang;Wen Wang;Yang Li;C. Dai;T. Tong;X. Shan;E. Charlson;S. Pei;X. Kong;Yandi Hu;A. Belyanin;G. Stein;Zhaoping Liu;Jonathan Hu;Zhiming Wang;J. Bao
尽管成功地将石墨烯建模为通过剥离或化学气相沉积（CVD）合成的0.34 nm厚的光学膜，但石墨烯诱导的金膜的表面等离子体共振（SPR）的位移仍然存在争议。在这里，我们通过开发一种清洁的CVD石墨烯转移方法并将Maxwell-Garnet有效介质理论（EMT）扩展到2D材料来解决这一争议。获得了0.24的SPR位移，并且它与其中褶皱石墨烯被处理为3-nm石墨烯/空气层状复合物的2D EMT很好地一致，与原子力显微镜测量的平均粗糙度一致。由于2D EMT的各向异性内置边界条件与石墨烯的光学各向异性兼容，因此石墨烯可以被建模为厚于0.34 nm的膜而不改变其光学性质;然而，其实际粗糙度，即，有效厚度将显著改变其对强面外场的响应，导致更大的SPR偏移。
Despite successful modeling of graphene as a 0.34-nm thick optical film synthesized by exfoliation or chemical vapor deposition (CVD), graphene induced shift of surface plasmon resonance (SPR) of gold films has remained controversial. Here we report the resolution of this controversy by developing a clean CVD graphene transfer method and extending Maxwell-Garnet effective medium theory (EMT) to 2D materials. A SPR shift of 0.24 is obtained and it agrees well with 2D EMT in which wrinkled graphene is treated as a 3-nm graphene/air layered composite, in agreement with the average roughness measured by atomic force microscope. Because the anisotropic built-in boundary condition of 2D EMT is compatible with graphene's optical anisotropy, graphene can be modelled as a film thicker than 0.34-nm without changing its optical property; however, its actual roughness, i.e., effective thickness will significantly alter its response to strong out-of-plane fields, leading to a larger SPR shift.